The present invention relates to a data signal monitoring method and apparatus, and more particularly, to a method and apparatus for monitoring, in a logic simulation, a data signal of a target circuit transmitted on a common bus in a system.
A microcomputer (CPU), a memory and an input/output circuit are connected to a common bus. The CPU operates according to program data stored in the memory to communicate a data signal including an instruction between the memory and the peripheral circuit.
A logic simulator is connected to the common bus to monitor whether one or more circuits operate normally. That is, the simulator monitors the data signal supplied to or output from a target circuit to check the operation of the target circuit. The simulator determines whether the monitored data signal matches an expected data signal corresponding to the operation of the system. Based on the determination result, whether the target circuit operates normally is determined.
However, because the system configuration is very complicated, many kinds of data signals are supplied on the common bus. This makes it difficult to monitor the target circuit data signal and the operation of the target circuit.
One method for monitoring a target circuit data signal traces all of the data signals on the common bus, displays the traced data signals on a CRT or other suitable display tool and separates the data signals to monitor the target circuit data signal. However, as the system configuration becomes more complicated, the system operation takes a longer time, and simulation for tracing the data signal also takes a longer time. Further, a large capacity memory is needed to trace the data signals for a long period of time. Therefore, it is disadvantageous in terms of cost and time to monitor the data signals by tracing.
An object of the present invention is to provide a method and apparatus which facilitate monitoring a data signal of a target circuit.